The present invention relates generally to heating, ventilation, air-conditioning and/or refrigeration (HVACR) systems. More particularly, the invention concerns automatic predictive maintenance method and apparatus for use with such systems.
When it is performed in accordance with a defined schedule, preventive maintenance of HVACR systems, and more particularly air conditioning and refrigeration systems, is time-consuming and costly. When preventive maintenance is not performed in accordance therewith, systems fail. Failures can occur at the worst possible time, and may result in significant economic loss, e.g. of inventory or equipment. The frequency with which preventive maintenance is performed is usually determined empirically and thus represents an actuarial approach that ignores equipment- or installation-specific requirements. Equipment maintenance based upon analytic concepts such as mean time between failures (MTBF) utilizes gross statistical averages that half the time fail themselves to achieve their failure-preventive purpose.